Well, I did put it the other way round: the players don't find it interesting because, for them, it is not interesting/
Eg maybe the situation is something about kobolds on a hill, and the players (in general; today; because of the PCs they're playing; some combination of factors; etc) simply aren't engaged by that sort of situation.
I don't know what a Vengaurak is. I know, therefore, that the stock play is to Magic Missile it. (Or am I confusing gazebos for darknesses?)
But more seriously, as well as not knowing what a Vangaurak is I also don't know what game I'm playing, what character I'm playing, and what makes this Vengaurak on this hill relevant to anything.
But, that's entirely the point.
We talk about the kobolds on the hill and we don't need a whole lot more than that, because, well, frankly, we're all experienced gamers and we know what a kobold is. At some point in our gaming history,
someone has described a kobold to us. Probably several someones over the years. So, now, we can basically take it as read that we know what a kobold is and what we should do if we see them.
But, a Vengaurak? Well, you don't know what that is. So, someone needs to explain to you what it looks like and what it wants. Now, here's two descriptions:
1. You know that cockroach monster at the end of Men in Black? That's more or less what you see.
2. Born of the blood of the glutton Titan Gaurak, "this hideous horse sized creature appears to be a twisted hybrid of beetle, mantis and maggot. It stinks of carrion and blood"
Now, the second description is a direct quote from the Creature Collection Revised for Scarred Lands. Which do you think would be more effective and needed at the table? Which do you think would be more likely to draw some sort of visceral reaction from the players? Which do think is the better description? After all, both get the description of the creature across pretty accurately.
Note, for reference, here's a Vengaurak: